Have a client who collects a deposit on their invoice. If the deposit is marked paid on the invoice you lose the ability to update it. If this general contractor then has additional charges for extras they have to create a second invoice. The only workaround so far has been to not document the deposit until project is completed or use a different invoicing system that he pays less than $10/month for. The only other option is mark the deposit refunded and redo the invoice. It is a lot of work for this client.